Rotary pump



y 1968 w. A. HAGEMANN 3,385,225

ROTARY PUMP Filed April 18, 1967 FIG. I.

a Na

FIG. 112 /13 H8 I05 IO7 d a I n 99 g loa Q/L I) 10'4 I 115 m0. 3 g IIOa.

INVENTOR WALTER A NTON IUS HAGEMANN DEZSQE STEINHERZ United States Patent "ice 3,385,225 ROTARY PUMP Walter Antonius Hagemann, Holstein, Germany, assignor to Siernen & Hinsch m.h.H., Itzeh-oe, Holstein, Germany (Iontinuation-in-part of application Ser. No. 467,949,

June 29, 1965. This application Apr. 18, 1967, Ser.

3 Claims. (Cl. 1193-405) ABSTRACT 6F THE DISCLOSURE A rotary multiple stage pump having a first impeller of a diameter smaller than the diameter of a succeeding impeller operating in a side channel chamber which extends to the inner surface of the peripheral wall of a substantially cylindrical casing common to both impellers. The difference in impeller diameters is sufficient to accommodate fluid-guiding means associated with the first impeller in the common casing which has a substantially uniform outer diameter.

This application is a continuation-in-part of co-pending application Ser. No. 467,949, filed June 29, 1965, now abandoned.

This invention relates to improvements in a rotary multiple stage pump, particularly for propelling liquids such as condensates, having a full-admission turbine impeller in the first stage and at least one succeeding partadmission side channel stage, the pump casing having a uniform outer diameter extending over both the full-admission and part-admission stages.

These pumps are known and are used in impelling condensate and are always used when unfavorable suction conditions are met, such as large suction heads or small intake heads. By a suitable construction of the fulladmission impeller in the first stage the suction capacity (net positive suction head) becomes particularly favorable, while the succeeding side channel stage or stages make it possible to produce a high pressure with a restricted number of stages and at a relatively low speed of rotation. Furthermore, these pumps may be self-priming, which is a requisite for many cases in use.

Prior pumps of this construction, however, have the disadvantage that the impeller diameter of the first fulladmission stage is comparatively large in relation to the impeller diameter of the succeeding side channel stage or stages. This leads to a relatively large casing diameter which results from the large size of the impeller of the first full-admission stage and the associated guide means for the fluid to be pumped, and which could be much smaller at the succeeding side channel stages. A pump of such construction is unnecessarily heavy and thus expensive.

In another prior type of pump, the casing diameter of the side channel stage is smaller than the casing di- :arneter of the full-admission stage. However, this results in a material disadvantage in that the two different outer diameters of the casing lead to a relatively complicated structure and a corresponding increase in cost. For example, it is necessary in such pumps to tie the parts of the casing by means of separate sets of bolts and to use relatively high pump supports and large connecting members.

Summary of the invention In a pump according to the invention, the inner surface of the peripheral wall of the casing is the radially outer boundary of the chamber of each side channel stage, and the diameter of the full-admission impeller is smaller than the diameter of each part-admission im- 3,385,225 Patented May 28, 1968 peller of each side channel stage by an amount sufiicient to accommodate the guide means of the full-admission stage in the space between the outer periphery of the full-admission impeller and the inner surface of the pump casing either entirely, or partly in this space and partly laterally of the full-admission impeller.

Because of the relatively small diameter of the fulladrnission impeller, sufiicient room remains in the casing (which then substantially over its entire length corresponds to the casing diameter of the succeeding side channel stage or stages) to accommodate the impeller of the first stage and also the associated guide means which may be a volute chamber or its equivalents, namely a guide wheel or a vaneless annular space. Due to the reduced diameter of the full-admission impeller, the delivery head of the first pump stage is naturally low, which however is unimportant, :as the first pump stage only serves to feed the pumped medium to the following side channel stage in such a Way that no cavitation occurs. Any desired increase in pressure is produced almost exclusively by the succeeding side channel stages.

As indicated hereinbefore, the diameter of the fulladmission impeller may be reduced to such an extent that the entire associated guide means is disposed radially outwardly of this impeller. It is, however, more advantageous to arrange the volute chamber or guide wheel or vaneless annular space of the first full-admission stage, partly laterally of the impeller. In this way it is possible, particularly with small pumps, to keep the diameter of the full-admission impeller to a desirable size, as between the impeller and the casing only enough room need be available to allow for the smallest permissible radial extension of the guide means.

The pump according to the invention is particularly advantageous when assembled as a glandless unit in combination with a motor having a drive shaft of the split tube type or with a magneto drive of such type.

Brief description of drawings In the drawings which illustrate the invention by way of example,

FIG. 1 is a longitudinal section through a multiple stage pump embodying the invention and having an annular vaneless guide chamber in the first full-admission stage.

FIG. 2 is a longitudinal section through the first stage and the adjacent stage of another embodiment of the invention, wherein the first full-admission stage includes a volute chamber;

FIG. 3 shows a tnansverse section taken on line 33 of FIG. 2 and illustrates a full-admission stage.

FIG. 4 is a longitudinal section through the first stage and the adjacent stage of a further embodiment of the invention, wherein the first full-admission stage is provided with a difiusion ring; and

FIG. 5 shows a transverse section taken on line 55 of FIG. 4 and illustrates a part-admission stage.

Description of preferred embodiments Referring to the drawings, each of the embodiments shown has a shaft 1'(FIG. l), 101 (FIGS. 2 and 3), 201 (FIGS. 4 and 5) which is mounted in bearings as indicated at 2, 162, 202 and driven by a motor 3. The suction end of the pump is provided with a suction or inlet casing member 6, 106, 2% having an inlet passage 7, 107, 207 therein for the admission of fluid, in particular liquid. As shown in FIG. 1, the other end of the pump is provided with a pressure or discharge casing member 8 which has an outlet passage 9 therein and at the same time serves to connect the pump to motor 3. In the embodiment of FIG. 1, the suction and discharge ,members 6 and 8 have integral supports 20, 21 thereon.

A generally cylindrical casing section 12, 112, 212 is connected to the coordinated suction member 6, 106, 206 and cooperates therewith to house the first pump stage which includes a full-admission impeller 4, 104, 204 actuated by shaft 1, 101, 201, respectively.

In FIG. 1, the first full-admission stage is of the circular casing type and has guide means in the form of an annular vaneless chamber 13 for receiving fluid from the impeller 4. The chamber 13 extends partly radially of the impeller, and partly laterally thereof in parallel to the axis of shaft 1 and in the direction towards the succeeding stage which will be described later.

In FIG. 2 and 3, the fluid-guiding means of the first stage is in the form of a volute chamber 113 which, like the chamber 13, extends partly radially of the impeller and partly laterally thereof as indicated at 113b. The inner limit of the volute chamber is shown at 113a in FIG. 3 and an outlet port is located in the area indicated at 117. One of the blades of the impeller 104 is shown at 104a.

In the embodiment of FIGS. 4 and 5, the fluid-guiding means of the first stage includes a diffusion Wheel or ring 213 and discharge channels 214.

Each of the embodiments illustrated includes one or more stages of the part-admission, side channel type as will now be set forth in detail. A generally cylindrical succeeding casing section 10 (FIG. 1), 110 (FIG. 2), 210 (FIGS. 4 and 5) is connected to the first stage for receiving fluid therefrom and cooperates with a generally cylindrical complementary casing section 11, 111, 211 to house the respective stage and enclose an annular impelling chamber 18, 118, 218 (FIG. 5) in which a partadmission impeller 5, 105, 205 operates. The casing sections 10, 110, 210 and 11, 111, 211 further serve as control discs for the side channel stages. Inner surfaces a, 116a, 210a and 11a, 1110, 211a of the radially outermost walls which latter have a predetermined, approximately minimum wall thickness constitute the radially outer boundaries of the annular chambers 18, 118, 218 and of side channels 19, 119, 219.

Referring to FIGS. 2 and 3, the outlet port referred to hereinbefore and located in the area 117 will permit passage of fluid from the first stage of the space between casing sections 112 and 110, and fluid will then enter the succeeding side channel stage through port 115 of easing section 110.

As shown in FIG. 5, the part-admission impeller 205 may be provided with radially disposed vanes 205a. Suction ports 215 which is located in front of the plane of FIG. 5 is indicated in dot-dash lines. An outlet port 216 of the side channel stage is formed by an opening in the wall of the side channel and serves to transfer fluid to an adjacent stage or, in the case of the last stage, to a discharge passage such as shown at 9 in FIG. 1.

To obtain a simple structure, the peripheral wall of the substantially cylindrical casing has a uniform outer diameter d and to render the pump compact and keep the radial extension of the casing as small as possible, the diameter d is made equal to the largest internal diameter d, (FIGS. 2 and 4) of the chamber of each side channel stage increased only by twice the predetermined, approximately minimum wall thickness of the outer peripheral wall of the casing, that is, the chamber extends fully to the inner surface of the peripheral wall of the casing so that unnecessary spaces are avoided in the radial direction. As indicated in FIG. 1, the diameter d, may at the same time be the largest internal diameter of the first stage of the pump. Diameter D of the full-admission impeller of the first stage is smaller than the diameter D of the part-admission impeller of each side channel stage by an amount suflicient to accommodate the fluid-guiding means 13; 113; 213 and 214 of the first stage within the casing of uniform outer diameter. Thus, the fluid-guiding means fits radially into the space between the full-admission impeller and the internal casing wall, the radial distance between the impeller and the wall being indicated by the reference character A in FIG. 1. As stated hereinbefcre, the guide means may partly be arranged laterally of the impeller, in particular in the case of an annular vaneless guide chamber or a volute chamber, and this will assist in keeping the diameter of the full-admission impeller within desirable limits.

Preferably, the largest radial or diametral internal dimension of the casing is substantially the same in the fulladmission stage and in the annular impelling chamber of each succeeding side channel stage. Thus, as previously indicated in connection with FIG. 1, the diameter d, applies in the first embodiment to the annular vaneless guide chamber 13 of the first stage as well as to the annular impelling chamber 18 of each side channel stage. In the case of the volute guide chamber 113 (FIGS. 2 and 3), the radial extension thereof preferably approximates the length of the largest internal radius of each side channel chamber 118. In the case of the diffusion ring 213 and discharge channels 214 (FIG. 4), the discharge channels preferably extend radially outwardly by a distance on the order of the length of the largest internal radius of each side channel chamber 218 (FIG. 5).

What is claimed is:

1. In an rotary multiple stage pump for propelling a 0 liquid, at substantially cylindrical Casing having a generally uniform outer diameter and including a first casing portion and at least one second casing portion, said second casing portion having an inner annular surface of largest internal diameter, a driven shaft mounted in said casing, a first pump stage in said first casing portion, a full-admission impeller arranged in said first stage and mounted on said shaft, a volute chamber in said first stage for receiving liquid from said impeller, at least one succeeding side channel stage arranged in said second casing portion and including an impeller chamber extending to said inner annular surface of largest internal diameter, and a partadmission impeller operating in said impeller chamber and mounted on said shaft, the diameter of said full-admission impeller being smaller than the diameter of said part-admission impeller by an amount sufficient to accommodate said volute chamber of the first stage within said first portion of the casing of generally uniform outer diameter, the radial extension of said volute chamber generally approximating the length of the radius of said inner annular surface to which said impeller chamber of the side channel stage extends.

2. In a rotary multiple stage pump for propelling a liquid, a substantially cylindrical casing having a generally uniform outer diameter and including a first casing portion and at least one second casing portion, said second casing portion having an inner annular surface of largest internal diameter, a driven shaft mounted in said casing, a first pump stage in said first casing portion, a full-admission impeller arranged in said first stage and mounted on said shaft, a diffusion ring and discharge channels in said first stage for receiving liquid from said impeller, at least one succeeding side channel stage arranged in said second casing portion and including an impeller chamber extending to said inner annular surface of largest internal diameter, and a part-admission impeller operating in said impeller chamber and mounted on said shaft, the diameter of said full-admission impeller being smaller than the diameter of said part-admission impeller by an amount suflicient to accommodate said diffusion ring and discharge channels of the first stage within said first portion of the casing of generally uniform outer diameter, said discharge channels extending radially outwardly by a distance generally on the order of the length of the radius of said inner annular surface to which said impeller chamber of the side channel stage extends.

3. In a rotary multiple stage pump for propelling a liquid, a substantially cylindrical casing having a generally uniform outer diameter and including a first casing portion and at least one second casing portion, said second casing portion having an inner annular surface of largest internal diameter, a driven shaft mounted in said casing, a first pump stage in said first casing portion, a fulladmission impeller arranged in said first stage and mounted on said shaft, an annular vaneless chamber in said first stage for receiving liquid from said impeller, at least one succeeding side channel stage arranged in said second casing portion and including an impeller chamber extending to said inner annular surface of largest internal diameter, and a part-admission impeller operating in said impeller chamber and mounted on said shaft, the diameter of said full-admission impeller being smaller than the diameter of said part-admission impeller by an amount sufiicient to accommodate said annular vaneless chamber of the first stage within the first portion of the casing of said annular vaneless chamber being approximately equal to the length of the radius of said inner annular surface to which said impeller chamber of the side channel stage extends.

References Cited UNITED STATES PATENTS 2,875,698 3/1959 Roth 103-105 3,154,020 10/ 1964 Sieghartner 103-108 3,247,797 4/ 1966 Sieghartner 10310S FOREIGN PATENTS 1,010,524 3/1952 France.

711,791 10/1941 Germany.

generally uniform outer diameter, the radial extension of 15 HENRY R RADUAZO Primary 

